Task.ContinueWith メソッド

public:
 System::Threading::Tasks::Task ^ ContinueWith(Action<System::Threading::Tasks::Task ^, System::Object ^> ^ continuationAction, System::Object ^ state, System::Threading::CancellationToken cancellationToken, System::Threading::Tasks::TaskContinuationOptions continuationOptions, System::Threading::Tasks::TaskScheduler ^ scheduler);

public System.Threading.Tasks.Task ContinueWith (Action<System.Threading.Tasks.Task,object> continuationAction, object state, System.Threading.CancellationToken cancellationToken, System.Threading.Tasks.TaskContinuationOptions continuationOptions, System.Threading.Tasks.TaskScheduler scheduler);

public System.Threading.Tasks.Task ContinueWith (Action<System.Threading.Tasks.Task,object>? continuationAction, object? state, System.Threading.CancellationToken cancellationToken, System.Threading.Tasks.TaskContinuationOptions continuationOptions, System.Threading.Tasks.TaskScheduler scheduler);

member this.ContinueWith : Action<System.Threading.Tasks.Task, obj> * obj * System.Threading.CancellationToken * System.Threading.Tasks.TaskContinuationOptions * System.Threading.Tasks.TaskScheduler -> System.Threading.Tasks.Task

Public Function ContinueWith (continuationAction As Action(Of Task, Object), state As Object, cancellationToken As CancellationToken, continuationOptions As TaskContinuationOptions, scheduler As TaskScheduler) As Task

パラメーター

戻り値

Task

新しい継続 Task。A new continuation Task.

例外

注釈

返されるは、 Task 現在のタスクが完了するまで実行されるようにスケジュールされません。The returned Task will not be scheduled for execution until the current task has completed. パラメーターで指定した条件 continuationOptions が満たされない場合、継続タスクはスケジュールではなくキャンセルされます。If the criteria specified through the continuationOptions parameter are not met, the continuation task will be canceled instead of scheduled.

public:
 System::Threading::Tasks::Task ^ ContinueWith(Action<System::Threading::Tasks::Task ^> ^ continuationAction, System::Threading::CancellationToken cancellationToken, System::Threading::Tasks::TaskContinuationOptions continuationOptions, System::Threading::Tasks::TaskScheduler ^ scheduler);

public System.Threading.Tasks.Task ContinueWith (Action<System.Threading.Tasks.Task> continuationAction, System.Threading.CancellationToken cancellationToken, System.Threading.Tasks.TaskContinuationOptions continuationOptions, System.Threading.Tasks.TaskScheduler scheduler);

member this.ContinueWith : Action<System.Threading.Tasks.Task> * System.Threading.CancellationToken * System.Threading.Tasks.TaskContinuationOptions * System.Threading.Tasks.TaskScheduler -> System.Threading.Tasks.Task

Public Function ContinueWith (continuationAction As Action(Of Task), cancellationToken As CancellationToken, continuationOptions As TaskContinuationOptions, scheduler As TaskScheduler) As Task

パラメーター

戻り値

Task

新しい継続 Task。A new continuation Task.

例外

例

System.threading.tasks.task.continuewith を使用して、バックグラウンドとユーザーインターフェイススレッドの両方で作業を実行する例を次に示します。The following is an example of using ContinueWith to run work both in the background and on the user interface threads.

private void Button1_Click(object sender, EventArgs e)  
{  
   var backgroundScheduler = TaskScheduler.Default;  
   var uiScheduler = TaskScheduler.FromCurrentSynchronizationContext();  
   Task.Factory.StartNew(delegate { DoBackgroundComputation(); },  
                         backgroundScheduler).  
   ContinueWith(delegate { UpdateUI(); }, uiScheduler).  
                ContinueWith(delegate { DoAnotherBackgroundComputation(); },  
                             backgroundScheduler).  
                ContinueWith(delegate { UpdateUIAgain(); }, uiScheduler);  
}  

Private Sub Button1_Click(ByVal sender As System.Object,   
                          ByVal e As System.EventArgs) Handles Button1.Click  
   Dim backgroundScheduler = TaskScheduler.Default  
   Dim uiScheduler = TaskScheduler.FromCurrentSynchronizationContext()  

   Task.Factory.StartNew(Sub()  
                           DoBackgroundComputation()  
                         End Sub, backgroundScheduler).ContinueWith(Sub(t)  
                            UpdateUI()  
                         End Sub, uiScheduler).ContinueWith(Sub(t)  
                            DoAnotherBackgroundComputation()  
                         End Sub, backgroundScheduler).ContinueWith(Sub(t)  
                            UpdateUIAgain()  
                         End Sub, uiScheduler)  
End Sub  

注釈

返されるは、 Task 現在のタスクが完了するまで実行されるようにスケジュールされません。The returned Task will not be scheduled for execution until the current task has completed. パラメーターで指定した条件 continuationOptions が満たされない場合、継続タスクはスケジュールではなくキャンセルされます。If the criteria specified through the continuationOptions parameter are not met, the continuation task will be canceled instead of scheduled.

public:
 System::Threading::Tasks::Task ^ ContinueWith(Action<System::Threading::Tasks::Task ^, System::Object ^> ^ continuationAction, System::Object ^ state, System::Threading::Tasks::TaskScheduler ^ scheduler);

public System.Threading.Tasks.Task ContinueWith (Action<System.Threading.Tasks.Task,object> continuationAction, object state, System.Threading.Tasks.TaskScheduler scheduler);

public System.Threading.Tasks.Task ContinueWith (Action<System.Threading.Tasks.Task,object>? continuationAction, object? state, System.Threading.Tasks.TaskScheduler scheduler);

member this.ContinueWith : Action<System.Threading.Tasks.Task, obj> * obj * System.Threading.Tasks.TaskScheduler -> System.Threading.Tasks.Task

Public Function ContinueWith (continuationAction As Action(Of Task, Object), state As Object, scheduler As TaskScheduler) As Task

パラメーター

戻り値

Task

新しい継続 Task。A new continuation Task.

例外

注釈

返されるは、 Task 現在のタスクが完了するまで実行されるようにスケジュールされません。実行が正常に完了したか、未処理の例外が原因でエラーが発生したか、または取り消されたため早期に終了したかのいずれかになります。The returned Task will not be scheduled for execution until the current task has completed, whether it completes due to running to completion successfully, faulting due to an unhandled exception, or exiting out early due to being canceled.

public:
 System::Threading::Tasks::Task ^ ContinueWith(Action<System::Threading::Tasks::Task ^, System::Object ^> ^ continuationAction, System::Object ^ state, System::Threading::Tasks::TaskContinuationOptions continuationOptions);

public System.Threading.Tasks.Task ContinueWith (Action<System.Threading.Tasks.Task,object> continuationAction, object state, System.Threading.Tasks.TaskContinuationOptions continuationOptions);

public System.Threading.Tasks.Task ContinueWith (Action<System.Threading.Tasks.Task,object>? continuationAction, object? state, System.Threading.Tasks.TaskContinuationOptions continuationOptions);

member this.ContinueWith : Action<System.Threading.Tasks.Task, obj> * obj * System.Threading.Tasks.TaskContinuationOptions -> System.Threading.Tasks.Task

Public Function ContinueWith (continuationAction As Action(Of Task, Object), state As Object, continuationOptions As TaskContinuationOptions) As Task

パラメーター

戻り値

Task

新しい継続 Task。A new continuation Task.

例外

注釈

返されるは、 Task 現在のタスクが完了するまで実行されるようにスケジュールされません。The returned Task will not be scheduled for execution until the current task has completed. パラメーターで指定した継続条件 continuationOptions が満たされない場合、継続タスクはスケジュールではなくキャンセルされます。If the continuation criteria specified through the continuationOptions parameter are not met, the continuation task will be canceled instead of scheduled.

public:
 System::Threading::Tasks::Task ^ ContinueWith(Action<System::Threading::Tasks::Task ^, System::Object ^> ^ continuationAction, System::Object ^ state, System::Threading::CancellationToken cancellationToken);

public System.Threading.Tasks.Task ContinueWith (Action<System.Threading.Tasks.Task,object> continuationAction, object state, System.Threading.CancellationToken cancellationToken);

public System.Threading.Tasks.Task ContinueWith (Action<System.Threading.Tasks.Task,object>? continuationAction, object? state, System.Threading.CancellationToken cancellationToken);

member this.ContinueWith : Action<System.Threading.Tasks.Task, obj> * obj * System.Threading.CancellationToken -> System.Threading.Tasks.Task

Public Function ContinueWith (continuationAction As Action(Of Task, Object), state As Object, cancellationToken As CancellationToken) As Task

パラメーター

戻り値

Task

新しい継続 Task。A new continuation Task.

例外

注釈

返されるは、 Task 現在のタスクが完了するまで実行されるようにスケジュールされません。実行が正常に完了したか、未処理の例外が原因でエラーが発生したか、または取り消されたため早期に終了したかのいずれかになります。The returned Task will not be scheduled for execution until the current task has completed, whether it completes due to running to completion successfully, faulting due to an unhandled exception, or exiting out early due to being canceled.

public:
 System::Threading::Tasks::Task ^ ContinueWith(Action<System::Threading::Tasks::Task ^, System::Object ^> ^ continuationAction, System::Object ^ state);

public System.Threading.Tasks.Task ContinueWith (Action<System.Threading.Tasks.Task,object> continuationAction, object state);

public System.Threading.Tasks.Task ContinueWith (Action<System.Threading.Tasks.Task,object>? continuationAction, object? state);

member this.ContinueWith : Action<System.Threading.Tasks.Task, obj> * obj -> System.Threading.Tasks.Task

Public Function ContinueWith (continuationAction As Action(Of Task, Object), state As Object) As Task

パラメーター

戻り値

Task

新しい継続タスク。A new continuation task.

例外

注釈

返されるは、 Task 現在のタスクが完了するまで実行されるようにスケジュールされません。実行が正常に完了したか、ハンドルされない例外が原因でエラーが発生したか、キャンセルによって早期に終了したことが原因です。The returned Task will not be scheduled for execution until the current task has completed, whether it completes due to running to completion successfully, faulting due to an unhandled exception, or exiting early due to cancellation.

public:
 System::Threading::Tasks::Task ^ ContinueWith(Action<System::Threading::Tasks::Task ^> ^ continuationAction, System::Threading::Tasks::TaskContinuationOptions continuationOptions);

public System.Threading.Tasks.Task ContinueWith (Action<System.Threading.Tasks.Task> continuationAction, System.Threading.Tasks.TaskContinuationOptions continuationOptions);

member this.ContinueWith : Action<System.Threading.Tasks.Task> * System.Threading.Tasks.TaskContinuationOptions -> System.Threading.Tasks.Task

Public Function ContinueWith (continuationAction As Action(Of Task), continuationOptions As TaskContinuationOptions) As Task

パラメーター

戻り値

Task

新しい継続 Task。A new continuation Task.

例外

例

次の例では、を使用して、 TaskContinuationOptions 継続元タスクが完了したときに継続タスクを同期的に実行するように指定しています。The following example demonstrates using TaskContinuationOptions to specify that a continuation task should run synchronously when the antecedent task completes. (が呼び出されたときに指定されたタスクが既に完了している場合 ContinueWith 、同期継続はを呼び出しているスレッドで実行され ContinueWith ます)。(If the specified task has already completed by the time ContinueWith is called, the synchronous continuation will run on the thread calling ContinueWith.)

public class TaskCounter  
{  
   private volatile int _count;  

   public void Track(Task t)  
   {  
      if (t == null) throw new ArgumentNullException("t");  
      Interlocked.Increment(ref _count);  
      t.ContinueWith(ct => Interlocked.Decrement(ref _count), TaskContinuationOptions.ExecuteSynchronously);  
   }  

   public int NumberOfActiveTasks { get { return _count; } }  
}  

Public Class TaskCounter  
   Private _count as Integer  

   Public Sub Track(ByVal t as Task)  
      If t is Nothing Then Throw New ArgumentNullException("t")  
      Interlocked.Increment(_count)  
      t.ContinueWith(Sub(ct)  
                        Interlocked.Decrement(_count)  
                     End Sub,  
                     TaskContinuationOptions.ExecuteSynchronously)  
   End Sub  

   Public ReadOnly Property NumberOfActiveTasks As Integer  
      Get  
         Return _count  
      End Get  
   End Property  
End Class  

注釈

返されるは、 Task 現在のタスクが完了するまで実行されるようにスケジュールされません。The returned Task will not be scheduled for execution until the current task has completed. パラメーターで指定した継続条件 continuationOptions が満たされない場合、継続タスクはスケジュールではなくキャンセルされます。If the continuation criteria specified through the continuationOptions parameter are not met, the continuation task will be canceled instead of scheduled.

public:
 System::Threading::Tasks::Task ^ ContinueWith(Action<System::Threading::Tasks::Task ^> ^ continuationAction, System::Threading::CancellationToken cancellationToken);

public System.Threading.Tasks.Task ContinueWith (Action<System.Threading.Tasks.Task> continuationAction, System.Threading.CancellationToken cancellationToken);

member this.ContinueWith : Action<System.Threading.Tasks.Task> * System.Threading.CancellationToken -> System.Threading.Tasks.Task

Public Function ContinueWith (continuationAction As Action(Of Task), cancellationToken As CancellationToken) As Task

パラメーター

戻り値

Task

新しい継続 Task。A new continuation Task.

例外

注釈

返されるは、 Task 現在のタスクが完了するまで実行されるようにスケジュールされません。実行が正常に完了したか、未処理の例外が原因でエラーが発生したか、または取り消されたため早期に終了したかのいずれかになります。The returned Task will not be scheduled for execution until the current task has completed, whether it completes due to running to completion successfully, faulting due to an unhandled exception, or exiting out early due to being canceled.

public:
 System::Threading::Tasks::Task ^ ContinueWith(Action<System::Threading::Tasks::Task ^> ^ continuationAction);

public System.Threading.Tasks.Task ContinueWith (Action<System.Threading.Tasks.Task> continuationAction);

member this.ContinueWith : Action<System.Threading.Tasks.Task> -> System.Threading.Tasks.Task

Public Function ContinueWith (continuationAction As Action(Of Task)) As Task

パラメーター

戻り値

Task

新しい継続 Task。A new continuation Task.

例外

例

次の例では、100のランダムな日付と時刻の値を配列に設定するタスクを定義します。The following example defines a task that populates an array with 100 random date and time values. ContinueWith(Action<Task>)配列が完全に設定されたら、メソッドを使用して、最も古い日付値と最新の日付値を選択します。It uses the ContinueWith(Action<Task>) method to select the earliest and the latest date values once the array is fully populated.

using System;
using System.Threading.Tasks;

public class Example
{
   public static void Main()
   {
      var firstTask = Task.Factory.StartNew( () => {
                               Random rnd = new Random();
                               DateTime[] dates = new DateTime[100];
                               Byte[] buffer = new Byte[8];
                               int ctr = dates.GetLowerBound(0);
                               while (ctr <= dates.GetUpperBound(0)) {
                                  rnd.NextBytes(buffer);
                                  long ticks = BitConverter.ToInt64(buffer, 0);
                                  if (ticks <= DateTime.MinValue.Ticks | ticks >= DateTime.MaxValue.Ticks)
                                     continue;

                                  dates[ctr] = new DateTime(ticks);
                                  ctr++;
                               }
                               return dates;
                            } ); 
                         
      Task continuationTask = firstTask.ContinueWith( (antecedent) => {
                             DateTime[] dates = antecedent.Result;
                             DateTime earliest = dates[0];
                             DateTime latest = earliest;
                             
                             for (int ctr = dates.GetLowerBound(0) + 1; ctr <= dates.GetUpperBound(0); ctr++) {
                                if (dates[ctr] < earliest) earliest = dates[ctr];
                                if (dates[ctr] > latest) latest = dates[ctr];
                             }
                             Console.WriteLine("Earliest date: {0}", earliest);
                             Console.WriteLine("Latest date: {0}", latest);
                          } );                      
      // Since a console application otherwise terminates, wait for the continuation to complete.
     continuationTask.Wait();
   }
}
// The example displays output like the following:
//       Earliest date: 2/11/0110 12:03:41 PM
//       Latest date: 7/29/9989 2:14:49 PM

Imports System.Threading.Tasks

Module Example
   Public Sub Main()
      Dim firstTask = Task.Factory.StartNew( Function()
                               Dim rnd As New Random()
                               Dim dates(99) As Date
                               Dim buffer(7) As Byte
                               Dim ctr As Integer = dates.GetLowerBound(0)
                               Do While ctr <= dates.GetUpperBound(0)
                                  rnd.NextBytes(buffer)
                                  Dim ticks As Long = BitConverter.ToInt64(buffer, 0)
                                  If ticks <= DateTime.MinValue.Ticks Or ticks >= DateTime.MaxValue.Ticks Then Continue Do

                                  dates(ctr) = New Date(ticks)
                                  ctr += 1
                               Loop
                               Return dates
                            End Function )
                         
      Dim continuationTask As Task = firstTask.ContinueWith( Sub(antecedent)
                             Dim dates() As Date = antecedent.Result
                             Dim earliest As Date = dates(0)
                             Dim latest As Date = earliest
                             
                             For ctr As Integer = dates.GetLowerBound(0) + 1 To dates.GetUpperBound(0)
                                If dates(ctr) < earliest Then earliest = dates(ctr)
                                If dates(ctr) > latest Then latest = dates(ctr)
                             Next
                             Console.WriteLine("Earliest date: {0}", earliest)
                             Console.WriteLine("Latest date: {0}", latest)
                          End Sub)                      
      ' Since a console application otherwise terminates, wait for the continuation to complete.
      continuationTask.Wait()
   End Sub
End Module
' The example displays output like the following:
'       Earliest date: 2/11/0110 12:03:41 PM
'       Latest date: 7/29/9989 2:14:49 PM

継続タスクが実行される前にコンソールアプリケーションが終了する可能性があるため、メソッドを呼び出して、この Wait() 例が終了する前に継続が実行を終了するようにします。Because a console application may terminate before the continuation task executes, the Wait() method is called to ensure that the continuation finishes executing before the example ends.

その他の例については、「 継続タスクを使用したタスクの連結」を参照してください。For an additional example, see Chaining Tasks by Using Continuation Tasks.

注釈

返されるは、 Task 現在のタスクが完了するまで実行されるようにスケジュールされません。実行が正常に完了したか、未処理の例外が原因でエラーが発生したか、または取り消されたため早期に終了したかのいずれかになります。The returned Task will not be scheduled for execution until the current task has completed, whether it completes due to running to completion successfully, faulting due to an unhandled exception, or exiting out early due to being canceled.

public:
 System::Threading::Tasks::Task ^ ContinueWith(Action<System::Threading::Tasks::Task ^> ^ continuationAction, System::Threading::Tasks::TaskScheduler ^ scheduler);

public System.Threading.Tasks.Task ContinueWith (Action<System.Threading.Tasks.Task> continuationAction, System.Threading.Tasks.TaskScheduler scheduler);

member this.ContinueWith : Action<System.Threading.Tasks.Task> * System.Threading.Tasks.TaskScheduler -> System.Threading.Tasks.Task

Public Function ContinueWith (continuationAction As Action(Of Task), scheduler As TaskScheduler) As Task

パラメーター

戻り値

Task

新しい継続 Task。A new continuation Task.

例外

注釈

返されるは、 Task 現在のタスクが完了するまで実行されるようにスケジュールされません。実行が正常に完了したか、未処理の例外が原因でエラーが発生したか、または取り消されたため早期に終了したかのいずれかになります。The returned Task will not be scheduled for execution until the current task has completed, whether it completes due to running to completion successfully, faulting due to an unhandled exception, or exiting out early due to being canceled.

public:
generic <typename TResult>
 System::Threading::Tasks::Task<TResult> ^ ContinueWith(Func<System::Threading::Tasks::Task ^, System::Object ^, TResult> ^ continuationFunction, System::Object ^ state, System::Threading::Tasks::TaskContinuationOptions continuationOptions);

public System.Threading.Tasks.Task<TResult> ContinueWith<TResult> (Func<System.Threading.Tasks.Task,object,TResult> continuationFunction, object state, System.Threading.Tasks.TaskContinuationOptions continuationOptions);

public System.Threading.Tasks.Task<TResult>? ContinueWith<TResult> (Func<System.Threading.Tasks.Task,object,TResult>? continuationFunction, object state, System.Threading.Tasks.TaskContinuationOptions continuationOptions);

member this.ContinueWith : Func<System.Threading.Tasks.Task, obj, 'Result> * obj * System.Threading.Tasks.TaskContinuationOptions -> System.Threading.Tasks.Task<'Result>

Public Function ContinueWith(Of TResult) (continuationFunction As Func(Of Task, Object, TResult), state As Object, continuationOptions As TaskContinuationOptions) As Task(Of TResult)

型パラメーター

パラメーター

戻り値

Task<TResult>

新しい継続 Task<TResult>。A new continuation Task<TResult>.

例外

注釈

返されるは、 Task<TResult> 現在のタスクが完了するまで実行されるようにスケジュールされません。The returned Task<TResult> will not be scheduled for execution until the current task has completed. パラメーターで指定した継続条件 continuationOptions が満たされない場合、継続タスクはスケジュールではなくキャンセルされます。If the continuation criteria specified through the continuationOptions parameter are not met, the continuation task will be canceled instead of scheduled.

public:
generic <typename TResult>
 System::Threading::Tasks::Task<TResult> ^ ContinueWith(Func<System::Threading::Tasks::Task ^, System::Object ^, TResult> ^ continuationFunction, System::Object ^ state, System::Threading::CancellationToken cancellationToken, System::Threading::Tasks::TaskContinuationOptions continuationOptions, System::Threading::Tasks::TaskScheduler ^ scheduler);

public System.Threading.Tasks.Task<TResult> ContinueWith<TResult> (Func<System.Threading.Tasks.Task,object,TResult> continuationFunction, object state, System.Threading.CancellationToken cancellationToken, System.Threading.Tasks.TaskContinuationOptions continuationOptions, System.Threading.Tasks.TaskScheduler scheduler);

public System.Threading.Tasks.Task<TResult> ContinueWith<TResult> (Func<System.Threading.Tasks.Task,object,TResult>? continuationFunction, object? state, System.Threading.CancellationToken cancellationToken, System.Threading.Tasks.TaskContinuationOptions continuationOptions, System.Threading.Tasks.TaskScheduler scheduler);

member this.ContinueWith : Func<System.Threading.Tasks.Task, obj, 'Result> * obj * System.Threading.CancellationToken * System.Threading.Tasks.TaskContinuationOptions * System.Threading.Tasks.TaskScheduler -> System.Threading.Tasks.Task<'Result>

Public Function ContinueWith(Of TResult) (continuationFunction As Func(Of Task, Object, TResult), state As Object, cancellationToken As CancellationToken, continuationOptions As TaskContinuationOptions, scheduler As TaskScheduler) As Task(Of TResult)

型パラメーター

パラメーター

戻り値

Task<TResult>

新しい継続 Task<TResult>。A new continuation Task<TResult>.

例外

注釈

返されるは、 Task<TResult> 現在のタスクが完了するまで実行されるようにスケジュールされません。The returned Task<TResult> will not be scheduled for execution until the current task has completed. パラメーターで指定した条件 continuationOptions が満たされない場合、継続タスクはスケジュールではなくキャンセルされます。If the criteria specified through the continuationOptions parameter are not met, the continuation task will be canceled instead of scheduled.

public:
generic <typename TResult>
 System::Threading::Tasks::Task<TResult> ^ ContinueWith(Func<System::Threading::Tasks::Task ^, TResult> ^ continuationFunction, System::Threading::CancellationToken cancellationToken, System::Threading::Tasks::TaskContinuationOptions continuationOptions, System::Threading::Tasks::TaskScheduler ^ scheduler);

public System.Threading.Tasks.Task<TResult> ContinueWith<TResult> (Func<System.Threading.Tasks.Task,TResult> continuationFunction, System.Threading.CancellationToken cancellationToken, System.Threading.Tasks.TaskContinuationOptions continuationOptions, System.Threading.Tasks.TaskScheduler scheduler);

member this.ContinueWith : Func<System.Threading.Tasks.Task, 'Result> * System.Threading.CancellationToken * System.Threading.Tasks.TaskContinuationOptions * System.Threading.Tasks.TaskScheduler -> System.Threading.Tasks.Task<'Result>

Public Function ContinueWith(Of TResult) (continuationFunction As Func(Of Task, TResult), cancellationToken As CancellationToken, continuationOptions As TaskContinuationOptions, scheduler As TaskScheduler) As Task(Of TResult)

型パラメーター

パラメーター

戻り値

Task<TResult>

新しい継続 Task<TResult>。A new continuation Task<TResult>.

例外

例

次の例は、System.threading.tasks.task.continuewith メソッドを継続オプションと共に使用する方法を示しています。The following example shows how to use the ContinueWith method with continuation options:

using System;
using System.Threading;
using System.Threading.Tasks;

class ContinuationOptionsDemo
{
    // Demonstrated features:
    //      TaskContinuationOptions
    //		Task.ContinueWith()
    // 		Task.Factory
    //		Task.Wait()
    // Expected results:
    // 		This sample demonstrates branched continuation sequences - Task+Commit or Task+Rollback.
    //      Notice that no if statements are used.
    //		The first sequence is successful - tran1 and commitTran1 are executed. rollbackTran1 is canceled.
    //		The second sequence is unsuccessful - tran2 and rollbackTran2 are executed. tran2 is faulted, and commitTran2 is canceled.
    // Documentation:
    //		http://msdn.microsoft.com/library/system.threading.tasks.taskcontinuationoptions(VS.100).aspx
    static void Main()
    {
        Action success = () => Console.WriteLine("Task={0}, Thread={1}: Begin successful transaction",
                                                Task.CurrentId, Thread.CurrentThread.ManagedThreadId);
        Action failure = () =>
        {
            Console.WriteLine("Task={0}, Thread={1}: Begin transaction and encounter an error",
                                Task.CurrentId, Thread.CurrentThread.ManagedThreadId);
            throw new InvalidOperationException("SIMULATED EXCEPTION");
        };

        Action<Task> commit = (antecendent) => Console.WriteLine("Task={0}, Thread={1}: Commit transaction",
                                                                Task.CurrentId, Thread.CurrentThread.ManagedThreadId);
        Action<Task> rollback = (antecendent) =>
        {
            // "Observe" your antecedent's exception so as to avoid an exception
            // being thrown on the finalizer thread
            var unused = antecendent.Exception;

            Console.WriteLine("Task={0}, Thread={1}: Rollback transaction",
                  Task.CurrentId, Thread.CurrentThread.ManagedThreadId);
        };

        // Successful transaction - Begin + Commit
        Console.WriteLine("Demonstrating a successful transaction");

        // Initial task
        // Treated as "fire-and-forget" -- any exceptions will be cleaned up in rollback continuation
        Task tran1 = Task.Factory.StartNew(success);

        // The following task gets scheduled only if tran1 completes successfully
        var commitTran1 = tran1.ContinueWith(commit, TaskContinuationOptions.OnlyOnRanToCompletion);

        // The following task gets scheduled only if tran1 DOES NOT complete successfully
        var rollbackTran1 = tran1.ContinueWith(rollback, TaskContinuationOptions.NotOnRanToCompletion);

        // For demo purposes, wait for the sample to complete
        commitTran1.Wait();

        // -----------------------------------------------------------------------------------

        // Failed transaction - Begin + exception + Rollback
        Console.WriteLine("\nDemonstrating a failed transaction");

        // Initial task
        // Treated as "fire-and-forget" -- any exceptions will be cleaned up in rollback continuation
        Task tran2 = Task.Factory.StartNew(failure);

        // The following task gets scheduled only if tran2 completes successfully
        var commitTran2 = tran2.ContinueWith(commit, TaskContinuationOptions.OnlyOnRanToCompletion);

        // The following task gets scheduled only if tran2 DOES NOT complete successfully
        var rollbackTran2 = tran2.ContinueWith(rollback, TaskContinuationOptions.NotOnRanToCompletion);

        // For demo purposes, wait for the sample to complete
        rollbackTran2.Wait();
    }
}

Imports System.Threading
Imports System.Threading.Tasks

Module ContuationOptionsDemo
    ' Demonstrated features:
    '   TaskContinuationOptions
    '   Task.ContinueWith()
    '   Task.Factory
    '   Task.Wait()
    ' Expected results:
    '   This sample demonstrates branched continuation sequences - Task+Commit or Task+Rollback.
    '   Notice that no if statements are used.
    '   The first sequence is successful - tran1 and commitTran1 are executed. rollbackTran1 is canceled.
    '   The second sequence is unsuccessful - tran2 and rollbackTran2 are executed. tran2 is faulted, and commitTran2 is canceled.
    ' Documentation:
    '   http://msdn.microsoft.com/library/system.threading.tasks.taskcontinuationoptions(VS.100).aspx
    Private Sub Main()
        Dim success As Action = Sub()
                                    Console.WriteLine("Task={0}, Thread={1}: Begin successful transaction", Task.CurrentId, Thread.CurrentThread.ManagedThreadId)
                                End Sub

        Dim failure As Action = Sub()
                                    Console.WriteLine("Task={0}, Thread={1}: Begin transaction and encounter an error", Task.CurrentId, Thread.CurrentThread.ManagedThreadId)
                                    Throw New InvalidOperationException("SIMULATED EXCEPTION")
                                End Sub

        Dim commit As Action(Of Task) = Sub(antecendent)
                                            Console.WriteLine("Task={0}, Thread={1}: Commit transaction", Task.CurrentId, Thread.CurrentThread.ManagedThreadId)
                                        End Sub

        Dim rollback As Action(Of Task) = Sub(antecendent)
                                              ' "Observe" your antecedent's exception so as to avoid an exception
                                              ' being thrown on the finalizer thread
                                              Dim unused = antecendent.Exception

                                              Console.WriteLine("Task={0}, Thread={1}: Rollback transaction", Task.CurrentId, Thread.CurrentThread.ManagedThreadId)
                                          End Sub

        ' Successful transaction - Begin + Commit
        Console.WriteLine("Demonstrating a successful transaction")

        ' Initial task
        ' Treated as "fire-and-forget" -- any exceptions will be cleaned up in rollback continuation
        Dim tran1 As Task = Task.Factory.StartNew(success)

        ' The following task gets scheduled only if tran1 completes successfully
        Dim commitTran1 = tran1.ContinueWith(commit, TaskContinuationOptions.OnlyOnRanToCompletion)

        ' The following task gets scheduled only if tran1 DOES NOT complete successfully
        Dim rollbackTran1 = tran1.ContinueWith(rollback, TaskContinuationOptions.NotOnRanToCompletion)

        ' For demo purposes, wait for the sample to complete
        commitTran1.Wait()

        ' -----------------------------------------------------------------------------------


        ' Failed transaction - Begin + exception + Rollback 
        Console.WriteLine(vbLf & "Demonstrating a failed transaction")

        ' Initial task
        ' Treated as "fire-and-forget" -- any exceptions will be cleaned up in rollback continuation
        Dim tran2 As Task = Task.Factory.StartNew(failure)

        ' The following task gets scheduled only if tran2 completes successfully
        Dim commitTran2 = tran2.ContinueWith(commit, TaskContinuationOptions.OnlyOnRanToCompletion)

        ' The following task gets scheduled only if tran2 DOES NOT complete successfully
        Dim rollbackTran2 = tran2.ContinueWith(rollback, TaskContinuationOptions.NotOnRanToCompletion)

        ' For demo purposes, wait for the sample to complete
        rollbackTran2.Wait()
    End Sub
End Module

注釈

返されるは、 Task<TResult> 現在のタスクが完了するまで実行されるようにスケジュールされません。The returned Task<TResult> will not be scheduled for execution until the current task has completed. パラメーターで指定した条件 continuationOptions が満たされない場合、継続タスクはスケジュールではなくキャンセルされます。If the criteria specified through the continuationOptions parameter are not met, the continuation task will be canceled instead of scheduled.

public:
generic <typename TResult>
 System::Threading::Tasks::Task<TResult> ^ ContinueWith(Func<System::Threading::Tasks::Task ^, System::Object ^, TResult> ^ continuationFunction, System::Object ^ state, System::Threading::Tasks::TaskScheduler ^ scheduler);

public System.Threading.Tasks.Task<TResult> ContinueWith<TResult> (Func<System.Threading.Tasks.Task,object,TResult> continuationFunction, object state, System.Threading.Tasks.TaskScheduler scheduler);

public System.Threading.Tasks.Task<TResult> ContinueWith<TResult> (Func<System.Threading.Tasks.Task,object,TResult>? continuationFunction, object? state, System.Threading.Tasks.TaskScheduler scheduler);

member this.ContinueWith : Func<System.Threading.Tasks.Task, obj, 'Result> * obj * System.Threading.Tasks.TaskScheduler -> System.Threading.Tasks.Task<'Result>

Public Function ContinueWith(Of TResult) (continuationFunction As Func(Of Task, Object, TResult), state As Object, scheduler As TaskScheduler) As Task(Of TResult)

型パラメーター

パラメーター

戻り値

Task<TResult>

新しい継続 Task<TResult>。A new continuation Task<TResult>.

例外

注釈

返されるは、 Task<TResult> 現在のタスクが完了するまで実行されるようにスケジュールされません。実行が正常に完了したか、未処理の例外が原因でエラーが発生したか、または取り消されたため早期に終了したかのいずれかになります。The returned Task<TResult> will not be scheduled for execution until the current task has completed, whether it completes due to running to completion successfully, faulting due to an unhandled exception, or exiting out early due to being canceled.

public:
generic <typename TResult>
 System::Threading::Tasks::Task<TResult> ^ ContinueWith(Func<System::Threading::Tasks::Task ^, System::Object ^, TResult> ^ continuationFunction, System::Object ^ state, System::Threading::CancellationToken cancellationToken);

public System.Threading.Tasks.Task<TResult> ContinueWith<TResult> (Func<System.Threading.Tasks.Task,object,TResult> continuationFunction, object state, System.Threading.CancellationToken cancellationToken);

public System.Threading.Tasks.Task<TResult>? ContinueWith<TResult> (Func<System.Threading.Tasks.Task,object,TResult>? continuationFunction, object state, System.Threading.CancellationToken cancellationToken);

member this.ContinueWith : Func<System.Threading.Tasks.Task, obj, 'Result> * obj * System.Threading.CancellationToken -> System.Threading.Tasks.Task<'Result>

Public Function ContinueWith(Of TResult) (continuationFunction As Func(Of Task, Object, TResult), state As Object, cancellationToken As CancellationToken) As Task(Of TResult)

型パラメーター

パラメーター

戻り値

Task<TResult>

新しい継続 Task<TResult>。A new continuation Task<TResult>.

例外

注釈

返されるは、 Task<TResult> 現在のタスクが完了するまで実行されるようにスケジュールされません。実行が正常に完了したか、未処理の例外が原因でエラーが発生したか、または取り消されたため早期に終了したかのいずれかになります。The returned Task<TResult> will not be scheduled for execution until the current task has completed, whether it completes due to running to completion successfully, faulting due to an unhandled exception, or exiting out early due to being canceled.

public:
generic <typename TResult>
 System::Threading::Tasks::Task<TResult> ^ ContinueWith(Func<System::Threading::Tasks::Task ^, System::Object ^, TResult> ^ continuationFunction, System::Object ^ state);

public System.Threading.Tasks.Task<TResult> ContinueWith<TResult> (Func<System.Threading.Tasks.Task,object,TResult> continuationFunction, object state);

public System.Threading.Tasks.Task<TResult>? ContinueWith<TResult> (Func<System.Threading.Tasks.Task,object,TResult>? continuationFunction, object state);

member this.ContinueWith : Func<System.Threading.Tasks.Task, obj, 'Result> * obj -> System.Threading.Tasks.Task<'Result>

Public Function ContinueWith(Of TResult) (continuationFunction As Func(Of Task, Object, TResult), state As Object) As Task(Of TResult)

型パラメーター

パラメーター

戻り値

Task<TResult>

新しい継続 Task<TResult>。A new continuation Task<TResult>.

例外

注釈

返されるは、 Task<TResult> 現在のタスクが完了するまで実行されるようにスケジュールされません。実行が正常に完了したか、未処理の例外が原因でエラーが発生したか、または取り消されたため早期に終了したかのいずれかになります。The returned Task<TResult> will not be scheduled for execution until the current task has completed, whether it completes due to running to completion successfully, faulting due to an unhandled exception, or exiting out early due to being canceled.

public:
generic <typename TResult>
 System::Threading::Tasks::Task<TResult> ^ ContinueWith(Func<System::Threading::Tasks::Task ^, TResult> ^ continuationFunction, System::Threading::Tasks::TaskContinuationOptions continuationOptions);

public System.Threading.Tasks.Task<TResult> ContinueWith<TResult> (Func<System.Threading.Tasks.Task,TResult> continuationFunction, System.Threading.Tasks.TaskContinuationOptions continuationOptions);

member this.ContinueWith : Func<System.Threading.Tasks.Task, 'Result> * System.Threading.Tasks.TaskContinuationOptions -> System.Threading.Tasks.Task<'Result>

Public Function ContinueWith(Of TResult) (continuationFunction As Func(Of Task, TResult), continuationOptions As TaskContinuationOptions) As Task(Of TResult)

型パラメーター

パラメーター

戻り値

Task<TResult>

新しい継続 Task<TResult>。A new continuation Task<TResult>.

例外

注釈

返されるは、 Task<TResult> 現在のタスクが完了するまで実行されるようにスケジュールされません。The returned Task<TResult> will not be scheduled for execution until the current task has completed. パラメーターで指定した継続条件 continuationOptions が満たされない場合、継続タスクはスケジュールではなくキャンセルされます。If the continuation criteria specified through the continuationOptions parameter are not met, the continuation task will be canceled instead of scheduled.

public:
generic <typename TResult>
 System::Threading::Tasks::Task<TResult> ^ ContinueWith(Func<System::Threading::Tasks::Task ^, TResult> ^ continuationFunction, System::Threading::CancellationToken cancellationToken);

public System.Threading.Tasks.Task<TResult> ContinueWith<TResult> (Func<System.Threading.Tasks.Task,TResult> continuationFunction, System.Threading.CancellationToken cancellationToken);

member this.ContinueWith : Func<System.Threading.Tasks.Task, 'Result> * System.Threading.CancellationToken -> System.Threading.Tasks.Task<'Result>

Public Function ContinueWith(Of TResult) (continuationFunction As Func(Of Task, TResult), cancellationToken As CancellationToken) As Task(Of TResult)

型パラメーター

パラメーター

戻り値

Task<TResult>

新しい継続 Task<TResult>。A new continuation Task<TResult>.

例外

注釈

返されるは、 Task<TResult> 現在のタスクが完了するまで実行されるようにスケジュールされません。実行が正常に完了したか、未処理の例外が原因でエラーが発生したか、または取り消されたため早期に終了したかのいずれかになります。The returned Task<TResult> will not be scheduled for execution until the current task has completed, whether it completes due to running to completion successfully, faulting due to an unhandled exception, or exiting out early due to being canceled.

public:
generic <typename TResult>
 System::Threading::Tasks::Task<TResult> ^ ContinueWith(Func<System::Threading::Tasks::Task ^, TResult> ^ continuationFunction, System::Threading::Tasks::TaskScheduler ^ scheduler);

public System.Threading.Tasks.Task<TResult> ContinueWith<TResult> (Func<System.Threading.Tasks.Task,TResult> continuationFunction, System.Threading.Tasks.TaskScheduler scheduler);

member this.ContinueWith : Func<System.Threading.Tasks.Task, 'Result> * System.Threading.Tasks.TaskScheduler -> System.Threading.Tasks.Task<'Result>

Public Function ContinueWith(Of TResult) (continuationFunction As Func(Of Task, TResult), scheduler As TaskScheduler) As Task(Of TResult)

型パラメーター

パラメーター

戻り値

Task<TResult>

新しい継続 Task<TResult>。A new continuation Task<TResult>.

例外

注釈

返されるは、 Task<TResult> 現在のタスクが完了するまで実行されるようにスケジュールされません。実行が正常に完了したか、未処理の例外が原因でエラーが発生したか、または取り消されたため早期に終了したかのいずれかになります。The returned Task<TResult> will not be scheduled for execution until the current task has completed, whether it completes due to running to completion successfully, faulting due to an unhandled exception, or exiting out early due to being canceled.

public:
generic <typename TResult>
 System::Threading::Tasks::Task<TResult> ^ ContinueWith(Func<System::Threading::Tasks::Task ^, TResult> ^ continuationFunction);

public System.Threading.Tasks.Task<TResult> ContinueWith<TResult> (Func<System.Threading.Tasks.Task,TResult> continuationFunction);

member this.ContinueWith : Func<System.Threading.Tasks.Task, 'Result> -> System.Threading.Tasks.Task<'Result>

Public Function ContinueWith(Of TResult) (continuationFunction As Func(Of Task, TResult)) As Task(Of TResult)

型パラメーター

パラメーター

戻り値

Task<TResult>

新しい継続タスク。A new continuation task.

例外

例

次の例は、System.threading.tasks.task.continuewith メソッドの使用方法を示しています。The following example shows how to use the ContinueWith method:

using System;
using System.Threading;
using System.Threading.Tasks;

class ContinuationSimpleDemo
{
    // Demonstrated features:
    // 		Task.Factory
    //		Task.ContinueWith()
    //		Task.Wait()
    // Expected results:
    // 		A sequence of three unrelated tasks is created and executed in this order - alpha, beta, gamma.
    //		A sequence of three related tasks is created - each task negates its argument and passes is to the next task: 5, -5, 5 is printed.
    //		A sequence of three unrelated tasks is created where tasks have different types.
    // Documentation:
    //		http://msdn.microsoft.com/library/system.threading.tasks.taskfactory_members(VS.100).aspx
    static void Main()
    {
        Action<string> action =
            (str) =>
                Console.WriteLine("Task={0}, str={1}, Thread={2}", Task.CurrentId, str, Thread.CurrentThread.ManagedThreadId);

        // Creating a sequence of action tasks (that return no result).
        Console.WriteLine("Creating a sequence of action tasks (that return no result)");
        Task.Factory.StartNew(() => action("alpha"))
            .ContinueWith(antecendent => action("beta"))        // Antecedent data is ignored
            .ContinueWith(antecendent => action("gamma"))
            .Wait();

        Func<int, int> negate =
            (n) =>
            {
                Console.WriteLine("Task={0}, n={1}, -n={2}, Thread={3}", Task.CurrentId, n, -n, Thread.CurrentThread.ManagedThreadId);
                return -n;
            };

        // Creating a sequence of function tasks where each continuation uses the result from its antecendent
        Console.WriteLine("\nCreating a sequence of function tasks where each continuation uses the result from its antecendent");
        Task<int>.Factory.StartNew(() => negate(5))
            .ContinueWith(antecendent => negate(antecendent.Result))		// Antecedent result feeds into continuation
            .ContinueWith(antecendent => negate(antecendent.Result))
            .Wait();

        // Creating a sequence of tasks where you can mix and match the types
        Console.WriteLine("\nCreating a sequence of tasks where you can mix and match the types");
        Task<int>.Factory.StartNew(() => negate(6))
            .ContinueWith(antecendent => action("x"))
            .ContinueWith(antecendent => negate(7))
            .Wait();
    }
}

Imports System.Threading
Imports System.Threading.Tasks

Module ContinuationDemo

    ' Demonstrated features:
    '   Task.Factory
    '   Task.ContinueWith()
    '   Task.Wait()
    ' Expected results:
    '   A sequence of three unrelated tasks is created and executed in this order - alpha, beta, gamma.
    '   A sequence of three related tasks is created - each task negates its argument and passes is to the next task: 5, -5, 5 is printed.
    '   A sequence of three unrelated tasks is created where tasks have different types.
    ' Documentation:
    '   http://msdn.microsoft.com/library/system.threading.tasks.taskfactory_members(VS.100).aspx
    Sub Main()
        Dim action As Action(Of String) = Sub(str) Console.WriteLine("Task={0}, str={1}, Thread={2}", Task.CurrentId, str, Thread.CurrentThread.ManagedThreadId)

        ' Creating a sequence of action tasks (that return no result).
        Console.WriteLine("Creating a sequence of action tasks (that return no result)")
        ' Continuations ignore antecedent data
        Task.Factory.StartNew(Sub() action("alpha")).ContinueWith(Sub(antecendent) action("beta")).ContinueWith(Sub(antecendent) action("gamma")).Wait()


        Dim negate As Func(Of Integer, Integer) = Function(n)
                                                      Console.WriteLine("Task={0}, n={1}, -n={2}, Thread={3}", Task.CurrentId, n, -n, Thread.CurrentThread.ManagedThreadId)
                                                      Return -n
                                                  End Function

        ' Creating a sequence of function tasks where each continuation uses the result from its antecendent
        Console.WriteLine(vbLf & "Creating a sequence of function tasks where each continuation uses the result from its antecendent")
        Task(Of Integer).Factory.StartNew(Function() negate(5)).ContinueWith(Function(antecendent) negate(antecendent.Result)).ContinueWith(Function(antecendent) negate(antecendent.Result)).Wait()


        ' Creating a sequence of tasks where you can mix and match the types
        Console.WriteLine(vbLf & "Creating a sequence of tasks where you can mix and match the types")
        Task(Of Integer).Factory.StartNew(Function() negate(6)).ContinueWith(Sub(antecendent) action("x")).ContinueWith(Function(antecendent) negate(7)).Wait()
    End Sub
End Module

注釈

返されるは、 Task<TResult> 現在のタスクが完了するまで実行されるようにスケジュールされません。実行が正常に完了したか、未処理の例外が原因でエラーが発生したか、または取り消されたため早期に終了したかのいずれかになります。The returned Task<TResult> will not be scheduled for execution until the current task has completed, whether it completes due to running to completion successfully, faulting due to an unhandled exception, or exiting out early due to being canceled.